Table 2 Radiological and smoking characteristics of study sample (n = 520).

	Number	%	95% CI
PTB on history	101	19.4	16.0 to 22.8
CXR prevalence of PTB—Reader 1	143	27.5	23.6 to 31.4
CXR prevalence of PTB—Reader 2	90	17.3	14.0 to 20.6
Prevalence of PTB on history or CXR—either reader	183	35.2	31.1 to 39.3
Silicosis 1/1 or greater—Reader 1	94	18.3	15.0 to 21.9
Silicosis 1/1 or greater—Reader 2	102	19.9	16.5 to 23.6
Silicosis 1/0 or greater—either reader	147	28.2	24.4 to 32.2
Ever smokers	267	51.3	47.0 to 55.7
Current smokers	150	28.8	24.9 to 32.8
Ex‐smokers	117	22.5	18.9 to 26.1

95% CI, 95% confidence interval; CXR, chest x ray.